“Collocation” herein refers to a semantically and grammatically meaningful combination of two or more words that has, in a chosen text corpus, a frequency exceeding a certain threshold. “Collocation” herein refers to a representation of a collocation in which at least some words are represented by their respective semantic classes. Dictionaries of collocations and collocations may be employed by various natural language processing methods, such as information extraction and/or natural language translation methods.